By David Lindenmayer, Australian National University
By any scientific yardstick, forestry operations in Victoria cannot be regarded as ecologically sustainable. Much of the attention of politicians, policy makers and the general public has been on the tall forests of Tasmania. But the state of Victoria’s forests is far worse than those in Tasmania – in terms of the number of species of conservation concern, the rate of overcutting, the loss of old growth forests, and the continued application of antiquated and environmentally-damaging clearfelling operations.
The Holy Grail of forest management is for it to be ecologically sustainable. Ecologically Sustainable Forest Management (ESFM) is defined as:
perpetuating ecosystem integrity while continuing to provide wood and non-wood values; where ecosystem integrity means the maintenance of forest structure, species composition, and the rate of ecological processes and functions within the bounds of normal disturbance regimes.
Loss of old growth forest
Our data gathered from nearly 30 years of work suggests that the area of old growth Mountain Ash forest at the time of white settlement would have typically been in the order of 60-80% of the total area of that forest type. It is currently around 1885 ha or 1.16% and is highly fragmented.
The loss of old growth forest is important because of the critical importance of large old trees as habitat for endangered wildlife like Leadbeater’s Possum – the faunal emblem of Victoria. The massive reduced area and fragmented nature of remaining old growth forest also threatens the viability of other iconic mammals. These include species strongly associated with large intact areas of old growth in Mountain Ash forests like the Yellow-bellied Glider.
The loss of old growth forest has arisen because of recurrent and widespread logging, repeated wildfires, and post-fire salvage logging. Logging is fundamentally altering the structure of stands of Mountain Ash forest as well as the composition of Mountain Ash forest landscapes. This means that logging operations cannot be considered to be ecologically sustainable.
Extinction of species
The paucity of old growth Mountain Ash forest, coupled with the widespread loss of large old trees means there is a significant and prolonged shortage of key nesting and denning resources for cavity-dependent species. Leadbeater’s Possum isn’t the only species on an extinction trajectory: more than 30 other cavity-using animals are at risk of localised extinction in Mountain Ash forests. Logging, fire, and the interactions between logging and fire are the key factors that have the potential to drive Leadbeater’s Possum to extinction.
The long-term paucity of hollow-bearing trees in Mountain Ash forests has led to calls for the use of artificial hollows (especially nest boxes) to address the problem for Leadbeater’s Possum. This approach is ecologically ineffective. Even if nest boxes worked for Leadbeater’s Possum, nest boxes are an economically ineffective approach to forest and wildlife management.
Conserving Leadbeater’s Possum has long been recognised as a testcase of ecologically sustainable forest management. The loss of this and other cavity-dependent species from Mountain Ash forests will result in an altered composition of native animal species in these ecosystems. On this basis, logging practices cannot be considered to be ecologically sustainable.
Altered key ecosystem processes
The traditional form of logging in Mountain Ash forests is clearfelling. This alters fire regimes in these forests. Fire severity is significantly higher in stands that have been logged and regenerated in the past 10-40 years. Logging also changes the way fires spread in Mountain Ash landscapes.
The recruitment, decay and collapse of large old trees is a key ecological process in forests, woodlands and savannas worldwide. In Mountain Ash forests, clearfell logging significantly impairs the recruitment process for large old trees and rapidly accelerates their rate of loss.
These altered processes have major negative impacts on the structure, composition, species assemblages and overall integrity of Mountain Ash ecosystems. Therefore, based on the definition given at the beginning of this article, logging practices are not ecological sustainable.
Environmentally damaging logging practices
Clearfelling removes all of the merchantable stems in a 15-40 ha area – primarily for pulpwood or woodchip production. Debris (such as tree heads, bark and lateral branches) is left to dry then burned in a high-intensity fire to help regenerate new trees.
Clearfelling is an excellent system for re-growing uniform aged stands of young trees. But large old trees are virtually eliminated on clearfelled sites and many key species of plants are significantly reduced. Old growth understorey plants such as Soft Tree Ferns and Rough Tree Ferns is reduced by around 90% or more on logged sites. These plants play many key ecological roles in Mountain Ash forests.
Alternatives to clearfelling – such as the variable retention harvest system – have been proposed for more than a decade in Victorian forests. But there is no indication the Victorian Government will adopt this system, despite it having been successfully trialled in Mountain Ash forests. The Victorian Government lags well behind other Australian states and other nations when it comes to the use of ecologically sustainable logging practices.
Over-cutting and extinction of the sawlog industry
The most extensive areas of Mountain Ash forest remaining for logging are those that regenerated after the 1939 wildfires. This age of forest has been targeted for clearfelling for more than two decades.
Under the Victorian Government’s Timber Release Plan, 412 coupes (17,640ha) of 1939 Mountain Ash are proposed for clearfelling to 2016. This is out of around 38,000 ha currently available. Present cutting rates would exhaust the 1939 regrowth resource within around 15 years.
Older trees are needed to produce sawlogs, but there are very few stands of forest older than 1939 (and those remaining are critically important for wildlife conservation). Past and present overcutting will collapse the sawlog industry. The forest industry will increasingly be dominated by low value woodchips and pulpwood from young forest.
Tens of thousands of hectares of Mountain Ash forest were burned in the 2009 wildfires. But there has been no reduction in the sustained yield of timber and pulpwood from Mountain Ash forests. Indeed, senior Victorian Government officials have supported a policy of “no net loss of forest to industry”. This has ramped up pressure on the reduced available green (unburned) Mountain Ash forest, making over-cutting inevitable.
Current management policies will fail in their ability to continue to: “… provide wood and non-wood values” as required under the definition of ecologically sustainable forest management.
Ministers in the Victorian Government have called for a “balance” between timber and pulpwood production and conservation. I agree this is important. But the old growth Mountain Ash forest estate has been reduced to an estimated 1/60th of what it once was and species like Leadbeater’s Possum are on an extinction trajectory. The so-called balance is tipped radically toward what are demonstrably unsustainable forest management practices.
What needs to change?
The current state of Victoria’s Mountain Ash forests is a result of decades of unsustainable forest management practices. There is an urgent need for reform.
The timber and pulpwood resources in Mountain Ash forests are overcommitted. There is straight-forward science to rectify this problem; as my colleague Professor Michael McCarthy notes – “It only takes some simple maths to get a handle on the scale of the problem. These ideas have also been around for decades. It is time that the managers of these forests started taking note of the long-standing research.”
I estimate a 50-75% reduction in cutting rates is needed. Areas that are exempt from logging need to be transferred to an expanded reserve system where there is an increased chance that such stands can grow through to an old growth stage.
The Victorian and Australian governments need to agree on a “safety net” for workers in the Victorian Mountain Ash forests so they can permanently exit their unsustainable industry. The industry is already being subsidised by the taxpayer through the losses incurred by organisations such as VicForests. But exit packages are appropriate as Victorian Government agencies, together with industry lobby groups, have been those at the core of poor policies that have over-committed the forest.
There is no longer a place for clearfelling operations in Mountain Ash forests. Retention harvesting is safe and feasible. Alternatives to clearfelling should be adopted – albeit in a significantly reduced number of logging coupes than at present. Far fewer coupes need to be harvested as a result of a much-needed reduction in sustained yield.
Current management in Victoria is not ecologically sustainable forest management. The science is clear about the urgent changes that are needed. It is time for the policies to match the science.
David Lindenmayer receives funding from the Australian Research Council.